1. Field of the Invention
This invention relates to injection molding. In one of its aspects, the invention relates to a mold for forming plastic parts with small pinholes. In another of its aspects, the invention relates to a method of molding plastic parts with small pinholes.
2. Description of Related Art
Plastic articles with decorative outer surfaces are made by forming plastic parts with a multitude of pinholes, placing the plastic parts in a vacuum mold, placing a decorative film, such as vinyl, on the plastic part, drawing a vacuum through the plastic parts to conform the film tightly to the shape of the plastic parts and adhesively securing the film to the plastic parts. Typically, the pinholes are made in the plastic parts during an injection-molding process. The mold cavity has a multitude of cylindrical pins extending from one mold surface so that the pins are in contact with the mating mold surface. Thus, one pinhole is formed for every pin.
The pins sometimes wear or break, resulting in the formation of plastic where a pinhole should be. The parts thus formed require very careful inspection of each plastic part to make sure that all of the pinholes have been formed. If the pinholes have not been formed, they require drilling or scrapping of the parts. Frequently, a pin will break during a molding process but the breakage will not be detected for some time, thus resulting in the formation of a number of defective plastic parts. Thus, the present process is expensive in that it is labor intensive and is somewhat imprecise in that imperfect plastic parts are frequently made.